Transmission line r.-f. lobing unit



April 19, 1960 D H, LANCTOT 2,933,701

TRANSMISSION LINE R.F'. LOBING UNIT Filed April 8, 1957 2 Sheets-Sheet lO//g-f//Ae BY 250226 M HG, 3 Arron/evs April 19, 1960 n. H. LANcToTTRANSMISSION LINE R.F. LoBING UNIT 2 Sheets-Sheet 2 Filed -April B. 1957INVENTOR. DONALD H. LANCTOT BY ma/523%@ P coNNEcToR 62 *1 a2 ouTPuTcoNNecToR is OUTPUT ATTOR NE KS United States Patent() TRANSMISSION LINER.F. LOBING UNIT Donald H. Lanctot, Malibu, Calif., assigner, by mesneassignments, to Electronic Specialty Co., a corporation of CaliforniaApplication April 8, 1957, Serial No. 651,537

15 Claims. (Cl. S33-7) This invention relates generally to highfrequency elec-v trical switches and more particularly to an improvedelectro-mechanical lobing unit for switching high frequency electricalenergy from an input transmission line to two or more outputtransmission lines. For convenience of terminology, the transmissionlines discussed are in the form of co-axial cables, although it shouldbe understood that parallel wire lines and wave guides could be employedas transmission carriers for the electrical energy involved.

High frequency lobing switches of the type under consideration areparticularly well adapted for switching high power, high frequencyelectrical energy between two or more antennas such as employed in radarsystems. In some instances, there may be provided a single reliectingtype antenna structure fed by two separate co-axial lines arranged to`deliver energy pulses alternately to the antenna from different focuspoints whereby the beam of the antenna is shifted between two limits. Inother instances, there may be a plurality of antennas which aresequentially energized to provide an effective lobel sweepingcharacteristic. It is important in all such lobing switches that minimumlosses occur during the switching operation and that a proper impedancematch be retained between the input and the various output lines'standpoint to insure relatively uniform and proper kirn-` pedancematching.

In order to effect switching of energy from an input line to two or moreoutput lines at a desired rate of speed; for example, live hundred timesper second, however, the problem of insuring positive connection bymetal to metal contact is rendered extremely difficult. Therefore, ininstances wherein a relatively rapid cyclic switching is desired,resortr is had to a capacitive coupling between the various innerconductors whereby no mechanical friction is introduced as a result ofmetal to metal contact. By means of such capacitive coupling, arelatively friction free unit may be provided with little mechanicaldiiculties. On the other hand, considerable losses are incurred as aresult of capacitive coupling, and further, the various energy portionsdistributed among the output lines are not positively defined.

In attempting to provide relatively rapid cyclic switching by means ofmetal to metal contacts between the various inner conductors, there is,in addition to friction, the problem of wear between the metal to metalcontact surfaces and the consequent problem of engineering a switch withsuiciently close tolerances to insure a satisfactory degree ofreliability, K A

iBearing the above in mind, it is a primary object of the presentinvcntion'to provide a greatly improved type of lobing switch in whichthe inner conductors of the various co-axial lines are positivelyconnected by a metal to metal engagement to enable discrete and equal orproportioned amounts of energy to be distributed between the variouslines with a minimum of electrical losses and mechanical friction and ata rate of anywhere from zero cycles to live or six hundred cycles persecond.

More particularly, it is an object to provide a switch of the above typewhich is positive throughout in operation and in which any wear of metalto metal contact points automatically compensates itself whereby anextremely reliable and substantially maintenance free unit results. f

These basic objectives as well as many other objects and advantages ofthe present invention are attained,y

are adapted to be respectively connected to two output` co-axial linesbetween which the energy in the input line is to be periodicallyswitched. The various co-axial connectors extend into one side of thecasing and terminate in the interior thereof.

A plurality of switching members respectively associated with theco-axial connectors are rotatably mounted on' a bearing plate within thehousing. These switchingk members include tapered probes extending froma cen-A tral conducting disc for the center co-axial connector switchingmember, and two conducting sector plates respectively associated withthe outside co-axial conductors to terminate in point contact means atthe` ends of the respective inner conductors for the co-axial connectom.The central disc and sector plates are positively geared together forrotation by a motor extending from the rear of the housing. The disc andsector plates themselves are substantially co-planar and arranged suchthat the sector plates overlap peripheral portions of the disc. Eachsector plate includes at least one sector element arranged to make ametal to metal contact with the periphery of the central disc, thesectors associated with each of the sector plates being of such relativeposition with respect to each other that the various connections betweenthe sectors and the central disc are made alternately upon rotation ofthe plates and disc by the driving motor. With this arrangement, itispossible to alternately switch electrical energy ,received in thecenter co-axial connector between the two outside co-axial connectors atanl extremely rapid rate. The casing for the various switchingcomponents is designed in a manner tok co-operate with the probesleading from the point contact means to insure a proper impedance matchbetween the various connectors. Further, theY entire unit ishermetically sealed and lled with oil of given dielectric constant.

A better understanding of the invention and its various features andadvantages will be had by referring to a more complete description of aspecific embodiment thereof as illustrated in the accompanying drawings,in which: Figure 1 is a perspective view of the lobing'unit forswitchingelectrical energy from an input co-axial line between twooutput co-axial lines; 1

Figure 2 is a plan view taken in the direction of the arrows 2 2illustrating the various switching components employed in the unit ofFigure l;

Figure 3 is an enlarged elevational view partly in cross sectionof oneof the point Ycontact means employed in the unit vof Figure 2;-l y -4 lFigure 4 vis an enlarged `perspective view of one of the elementsoft-the vpoint contact means; 4

Figure 5 4isfa cross sectional schematic view of a p01*' Patented Apr.y19, 1960 f answer p y n tion ofthe switching means taken in thedirection of the arrows 5 5 of lFigure 2;

Figure 6 is an enlarged cross section taken in the direction of thearrows 6 6 of Figure 5; K

Figure 7 illustrates ya modified type of sector plate which could beemployed in the switching apparatus of Figure 5;

Figure 8 is another schematic diagram illustrating one possiblerelationship of the driving gears for operating the switching unit,taken in the direction of the arrows 8 8 of Figure 2;

Figure 9 is an elevational view ofl the driving gears taken in thedirection of the arrows 9 9 of Figure 8; and,

Figure 10 is a time graph illustrating the output energy distributioneffected by the switching unit of this invention.

Referring to Figure l, there is illustrated a hollow casing 11i on thefront face of which is mounted a center co-axial connector 11 and twooutside co-axial connectors 12 and 13. lIn the embodiment shown inFigure 1 for the sake of illustration, the center co-axial connector 11is adapted to be connected to an input co-axial line from a highfrequency oscillator such as a magnetron or other source of highfrequency electrical energy, while the two outside co-axial connectors12 and 13 are adaptedy to be respectively connected to two outputco-axial lines leading to a pair of antennas or other type radiating ortransmitting device. The switching arrangement within the casing 10 issuch that energy entering the center coaxial connector 11 will bealternately switched between the output co-axial connectors 12 and 13. Aportion of the unit also includes a driving motor 14 extending from therear of the casing 10 for effecting this switching operation. The motor14 is provided at its rear with an inlet 15 for connection to anelectrical source to drive the motor. Preferably, the motor 14 is of thesynchronous type such that it will rotate at a precise, constant speed.

Referring now to the partial cross sectional plan view of Figure 2, itwill be noted that the outer conductorsof the various co-axialconnectors 11, 12 and 13 are all electrically connected together throughthe medium of the metal casing 10 while the inner conductors associatedwith these connectors are isolated from the casing by suitabledielectric material. As shown in Figure 2, the hollow interior of thecasing 10 is divided by a metallic bearing plate 16 extending completelyacross the unit to provide a first compartment 17 serving to house thevarious switching units to be described shortly and a second compartment18 serving to house various gearing associated with the switching unitsand driven by the motor 14.

The bearing plate 16 also serves as a mounting means for rotatablymounting a center switching member 19 and two outside switching members20 and 21 in co-axial alignment respectively with the center co-axialconnector 11 and the two outside co-axial connectors 12 and 13. Themanner in which these switching members are mounted in the bearing plate16 is identical and, therefore, description of the mounting arrangementand components of one will suffice for all. Referring to the lowerswitching member 21 of Figure 2, for example, there are provided ballbearings 22 for mounting the rear portion of the switching member to thebearing plate 16 and ball bearings 23 mounting the forward portion ofthe member 21 to the casing 10 adjacent the output co-axial connector13. The switching member 21 itself includes a tapered electricallyconducting probe 24 extending in the rst compartment 17 towards theoutput co-axial connector 13. The interior walls of the housing 10includeV similarly tapered portions as at 25, the angle of the interiortaper 25 being slightly greater than the taper 24 Such thatproportionate spacing between the housing 10,

serving as the outer conductor, and the tapered probe Y24, serving asthe inner conductor, with respect to the varying diameter of the innerconductor, is maintained. By this arrangement, a proper impedance matchis provided from the output co-axial connector 13 to the switchingmember 21.

As shown in Figure 2, the tapering probe 24 terminates in a reduceddiameter end portion 26 providing an end point contact surface arrangedto make metal to metal contact with a point contactv means 27 positionedat the end of the inner conductor 28 of the output co-axial connector13. The reduced end portion 26 of the probe 24 corresponds in diameterto the diameter of the inner conductor 28 of the co-axial connector 13.Suitable dielectric material serves to support the inner conductor 28and end portion of the probe 26 in proper co-axial alignment, and theinner metal ball bearing race of the bearings 23 serves to co-operatewith the tapered metallic wall portions of the housing 10 to provide aneffective outer conductor for these inner conductors. The switchingmember 21 is rotatably mounted in the plate 16 such that rotation takesplace about the central axis of the tapering probe 24 whereby theextreme end portion 26 of this probe rotates against the point contactmeans 27 at the end of the stationary inner conductor 28. Similartapered probes and point contact means are included in the other twoswitching members 19 and 20.

As shown in Figure 2 and in greater detail in Figure 5, the taperedprobe for the center switching member 19 merges in and is electricallyconnected to a central conducting disc 29. The tapered probes for theswitching members 20 and 21 similarly are electrically connected tosector plates 30 and 31. The sector plates are co-planar with thecentral disc and dimensioned to overlap the periphery of the disc whenthe rotatable switching members 19, 20 and 21 are rotated. These sectorplates and central disc constitute a transfer means for alternatelypass'- ing electrical energy from the central co-axial connector to theoutside co-axial connectors all as will become clearer as thedescription proceeds.

As shown in Figure v2, the switching members 20 and 21 include co-axialstubs including inner conductors 32 g and 33 electrically connected tothe tapered probes, such as the probe 24 for the switching member 21,and extending into and terminating within the second compartment 18.These stubs 32 and 33 respectively co-operate with the mounting bearingsfor the respective outside switching members 20 and 21 and the bearingplate 16 itself to provide a substantially uniform end wall lfor R.F.energy being transferred between the center co-axial connector and theoutside co-axial connectors, whereby electrical losses are minimizedwhen energy is being passed through the transfer means.

The various switching means 19, 20 and 21 are rotated by a suitablegeartrain in the second compartment 18. This gear train, as clearly shown inFigures 2, 8 and 9, may comprise, for example, a pinion 34 connecteddirectly to the shaft 35 of the motor 14 and meshing with a spur gear 36in turn connected to a second pinion 37 meshing with a center spur gear38directly secured to the center switching member 19. The center spurgear 38 is arranged to mesh directly with two outside spur gears 39 and40 directly secured to the switching members 20 and 21 respectively.Rotation of the center spur gear 38 will, therefore, rotate the spurgears 39 and 40 in the same direction and at exactly the same speed in apositive manner whereby the sector plates on the other side of thepartition bearing plate 16 will also be rotated exactly in synchronismwith respect to the center conducting disc 29. The gears 34, 36, and 37are merely reduction gears to provide -a proper operating speed for theswitching members.

Figure 3 shows in enlarged detail view the point contact meansassociated with the inner conductor 28 and tapering probe 24 for theoutside coaxial connector 13.y

This point contact means is characteristic of the other two connectionsto tapered probes for the switching members 19 and 20 and, therefore,description of one will suice for all. As shown in Figure 3, the innerconductor 28 has a tapered surface portion 41 conical in shape andthence merging into a reduced diameter nose portion 42. The pointcontact means 27 itself comprises a highly conductive cup element havinga plurality of slots in its sides to define ngers 43, 44, 45 and 46 asbest seen in Figure 4. The ends of these figures are adapted to ride onthe conical surface 41 and are biased laterally inwardly thereby tendingto move the element 27 in anaxial direction as indicated by the arrow tothe right, such that the bottom ofthe element 27 engages thecontactsurface 47 of the end portion 26 of the probe. The nose portion42 serves as a guide for this axial movement. This bottom portion of thecup 27 is made with precious metal to insure a long wearing contact withthe probe end. Because of the biasing of the springngers in engagementwith the conical surface 41, any Wearing of the inner engaging surfacesat 47, which may result under ordinary conditions in a loss of contact,is accommodated bythe constant urging of the cup bottom towards theprobe and by the action of the fingers against the conical surface 41.Thus, there is provided an automatic adjustment which is continuously inaction to rinsure positive electrical contact between the innerconductor 28 and the probe end portion 26.

The manner in which the transfer means comprising thevarious sectorplates 30 and 31 and the central disc 29 as described in connection withFigure 2 operate, will nowybe describedin detail with reference toFigures 5 and `6. InrFigure 5, it will be noted that the sector plate 30includes two sectors 48 and 49. In the embodiment `shown forillustrative purposes, these sectors may have an arcuate peripheralextent of substantially forty-` ve degrees each and extend diametricallyas shown. Similarly, the sector plate 31 includes two diametricallyoppositely extending sectors 50 and 51 each of substantially forty-fivedegrees of arc. The sectors 50 and 51 are positioned at ninety degreesrelative to the sectors 48 and 49 suchy that alternate contact with thecentral conducting disc 2.9 will be made by the respective sectors. Theoverall diameters of the sector plates 30 and 31 are such that theirperipheries will overlap the periphery of the'conducting disc 29. Asshown best in Figure 6, the

kcentral discV 29 in a preferred embodiment, actually includes' twocoaxial discs 5.2 and 53 secured together at their hubs to define aperipheral slot 54. The overlapping ofthe sectors is accommodated byreception of the sectors between the discs inthe slot 54. As a result ofthe differential speed` created by the overlapping, a wiping contact.will be made between the sector plates and the central conducting disccomprising thedual discs S2 and 53.

If it is assumed that the gear train drives the central conducting disc29 in a counter clockwise direction as viewed in Figure 5, then thesector plates 30 and 31 will be driven in a clockwise directionsimultaneously and .at the same rate of speed, all as indicated by thearrows. In this event, the sector portion 49 as shown will be enteringthe peripheral slot 54 and thus while so sandwiched within this slotelectrical energy will be passed from the center coaxial connector 11 tothe outside coaxial connector 12. Y

Just prior to termination of contact of the sector 49 with the innerside walls of the discs defining the slot 54 in thek conducting disc 29,the sector 51 associated with the sector plate 31 will enter the slot 54to make contact with thel conducting disc 29. The arcuate extent anddegreegof overlapping of the various plates and central disc may bedesigned such that one contact will be made before the other contact isbroken. By having a contact made before the other is broken, possiblearcing occasioned'by open circuits is avoided.

'In the cross sectional view of Figure 6 taken in the direction of thearrows 6-6 of Figure 5, it will be noted that the peripheral discsurfaces forthe discs 52 and 53 dening the slot 54 are directed inwardlyslightly to enable introduction of a spring bias so that the discs 52and 53 tend to grip opposite sides of the sector 49 thereby providing apositive engagement as at 55 and 56. To facilitate entry of the sectors,the edge and end portions thereof such as at 57 for the sector 49 aretapered slightly.

This manner of interconnection of the sector plates with the conductingdisc 29 is an important feature of the invention. to provide consistentcontact pressure coupled with the natural differential speeds introducedas a result of the overlapping, there is provided a self cleaning actionbetween these engaged metal to metal surfaces. Further, the inh'erentadditional advantages of capacitance coupling is realized because of therelatively large contact area between the metal contacting portions ofthe dual discs 52 and 53 sector 49.

The duration of the electrical connection between any one sector and thedisc may be varied by altering the arcuate extent of the sector.Further, the sectors on one sector plate may be dimensioned diierentlyfrom the sectors on the other sector plate in order to provide adistinguishing characteristic in the electrical signal transmitted toone of the coaxial connectors as compared to the other.

In Figure 7, for example, there is illustrated a sector plate 58 havingsector portions 59 and 60 provided with notches 61 such that severalmake and break connections are eected while the sectors 59 and 60aresandwiched within the slot 54. Thus, the output energy from thecorresponding coaxial connector is distinguished over that` fed to theother coaxial connector. As an alternative to the notching such as at61, the overall arcuate extent of the sectors 59 and 60 may be madedilferent from that of the sectors on the other sector plate whereby adistinguishing means is provided for the two output signals.

The overall operation of the entire lobing unit will be apparent fromthe above description. Referring once again to Figure 2 and to the plotin Figure l0, a source of electrical energy is connected to theelectrical inlet 15 for the motor 14 to drive the motor at a constantrate of speed. An inlet co-axial line passing from an electrical energysource (not shown) is connected to the center co-axial connector 11, andtwo output co-axial lines (notshown), leading to other units such asantennas between which the energy from the input co-axial line is to beswitched, are connected to the outside co-axial connectors 12 and 13.The input high frequency energy in the co-axial connector 11 is passedthrough the inner conductor thereof and the point contact cup means suchas illustrated in Figures 3 and 4 to the center probe associated withthe switching member 19 so that this energy appears on the conductingdisc 29. This disc is being rotated at' a given speed through the mediumof the gear train by motor 14 and simultaneously the outer sector plates30 and 31 are similarly being rotated. As best shown yin Figure 5, thesector plates'stl and 31 will thus alternately make electrical contactwith the conducting disc 29 thereby passing the high frequency energy atdisc 29 to one or the other of the sector plates 3i) and 31. From thesector plates 39 and 31, this electrical energy will pass down acorresponding tapered probe and point contact cup to the correspondinginner conductor of the outside co-axial connectors 12 and 13 to pass tothe output co-axial lines. The provision of the bearing plate partition16 as described heretofore, in co-operation with the co-axial stubs 32and 33 minimizes electrical losses during the transferring operationbetween the disc and sectors and delines essentially, with the remainingWalls Y' By sandwiching the sector within the slot 54 acens/or `Asmentioned heretofore, the unique point contact means 27 in the formofthe split cup Vof Figures 3 and 4 insures substantially maintenance freeand reliable operation ofthe unit. Further, the sandwiching provision inthe central conducting disc 29 provided by the dual disc constructionwith the peripheral portions of the sector plates, insures positiveelectrical contact during the switching operation. Any wear during thesecontacting periods is accommodated by biasing in of the side of thewalls of the discs 52 and 53 against the sector therewithin. Thedifferential speed as a result of the overlapping of the sectors andcentral disc provides wiping action as well as a cleaning action betweenthese contacting surfaces.

Because of the positive mechanical gearing and constant speed of themotor 14 as well as the positive arcuate dimensioning of the varioussectors, a discrete proportioning of the input electrical energy ismaintained. In Figure l0, for example, the distribution of this highfrequency energy between the two output co-axial connectors 12 and 13 isillustrated. Thus, with respect to time, the output of electrical energyfrom the co-axial connector 12is indicated by the shaded wave formk 62and the output of the co-axial connector 13 is indicated by the shadedportion 63. It will be noted that the durationy of each of the energiesdistributed between the output connectors is exactly equal as indicatedby P. Each output ofthe lobing unit thus provides a substantiallyperfect square wave, and to this end the lob-ing unit may readily beemployed as a square wave generator.

As mentioned heretofore, it may be desirable that the output from one ofthe co-axial connectors be distinguishable from the output from theother co-axial connector, and to this end one of the sector plates maybe dimensioned differently from the other. In the event suchdimensioning took the form of decreasing the arcuate extent of thesectors on the sector plate, this would effectively change the period Pfor the particular energy coming from one of the outputs as comparedwith the period P for the energy from the other output.

In the actual embodiment of the lobing switch unit, the entire interiorof the casing as illustrated in Figure 2 is filled with oil 64 of givendielectric constant and the whole unit is hermetically sealed. Sealingbetween the first and second compartments 17 and 18 insofar as the oilis concerned, however, is not necessary nor desirable. Actually, the oilwill permeate the motor 14 itself and ser-ve to lubricate all thegearing as well as the various ball bearings and will provide anexcellent operating and lubricating medium for the sector plates andconducting disc. Any sparking, for example, will be immediately quenchedby the oil and any generated heat will be readily transferred to thecasing 10 and properly dissipated. Further, the given dielectricconstant of the oil is ysuch as to provide a uniform impedance betweenthe tapered probes and interior tapering of the case 10 such thatimpedance matching is maintained throughout.

While the instant invention has been described with respect to aparticular embodiment in which a center coaxial connector is arranged toswitch electrical energy between only two output co-axial connectors, itshould be readily understood that additional output co-axial connectorsand associated tapered probes and switching units including properlydesigned sector plates may be incorporated without departing from thespirit of the invention. Thus, for example, because of the symmetry ofthe unit with respect to the central axis thereof passing through thecenter co-axial connector 11, two additional coi-axial connectorssimilar to 12 and 13l could be arranged above and below the connector 11as viewed in Figure l whereby electrical energy may be uniformlydistributed between four output co-axial connectors. It is also possibleto serially connect another set of switching members in co-axial tandemfashion with the switching members 19, 2t), and 21 and employ the samemotor driving means for rotating these mcmberson common shafts. Othersuch modifications falling within the scope and spirit of this inventionwill readily occur to those skilled in the art. The transmission lineR.F. lobing switch is, therefore, not to be thought of as limited to Ythe particular embodiment described and shown for illustrative purposes.

What is claimed is:

l. A lobing unit for switchingV high frequency electrical energy from aninput co-axial line between at least two output co-axial lines,comprising, inV combination: a central conducting disc and twoconducting sector plates; means rotatably mounting said disc and each ofsaid plates in substantially co-planar relationship; means for rotatingsaid disc and each of said plates in synchronism to produce synchronousrotation of said disc and said plates; said plates each including asector portion alternately making electrical contact with said centraldisc upon said synchronous rotation; and means electrically connectingsaid disc to the center conductor of said input co-axial line, and meansrespectively connecting electrically each of said sector plates to thecorresponding inner conductor of said output co-axial lines.

2. A lobing unit according to claim 1, in which said means electricallyconnecting said disc into the center conductor of said input co-axialline and said means respectively connecting said sector plates to theinner conductors of said output co-axial lines, each include a cupshapedconducting element having a plurality of slots in its side walls to denea plurality of fingers; the end p0rtions of said inner conductorstapering to a reduced diameter to dene conical surfaces against whichsaid' fingers seat; probes on said central disc and outside sectorplates respectively extending `towards said inner conductors toterminate adjacent the bottom of each cup associated therewith and tomake point Contact therewith, said fingers on each cup being biasedlaterally outwardly by the corresponding conical surface at the endportion of the corresponding inner conductor whereby said cup is axiallyurged towards the ends of said probes to maintain said point contact.

3. A lobing unit for switching high frequency electrical energy from aninput co-axial line between at least two output co-axial lines,comprising, in combination: a hollow casing; a center coaxial connectorand two outside co-axial connectors passing into said casing, saidcenter co-axial connector being adapted for connection to said n inputco-axial line and said two outside co-axial connectors beingrespectively adapted for connection to said two output co-axial lines; abearing plate positioned in said casing to divide the hollow interiorthereof into `iirst and second compartments; a center switching meansand two outside switching means rotatably mounted in said bearing platein co-axial alignment respectively with said center co-axial connectorand saidtwo outside co-axial connectors; said center switching meansincluding a probe extending into said first compartment and terminatinginV a contact surface adjacent the end of the inner conductor of saidcenter co-axial connector; point contact means -positioned betweensaid'contact surface and said inner conductor for passing saidelectrical energy fromssaid center co-axial connector to said centerswitching means; transfer means for alternately passingsaidelectricalienergy to said outside switching means upon rotation ofysaid center switching means and said outside switching.

means, said outside switching means respectively including probesextending into said first compartment and terminating in contactsurfaces adjacent the ends of the inner conductors of said outsideco-axial connectors; point contact means positioned between said contactsurfaces and said inner conductors for passing said electrical energyfrom said outside switching means to said voutside co-axial connectors;gear means in Vsaid second compartment positively interconnecting saidcenter switching means with said two outside switching means; and motormeans for driving said gear means to rotate Said Center 9 switchingmeans and said two outside switching means whereby said energy is passedby said transfer means from said center switching means alternately tosaid two outsideV switching means.

4. A unit according to claim 3, in which said point contact means forpassing electrical energy from said center co-axial connector to saidcenter switching means and said point contact means for passing saidelectrical energy from said outside switching means to said outsideco-axial connectors comprise cup-shaped highly conductive elementshaving lateral slots in their side walls defining a plurality offingers, the terminal end of said inner conductor for said centerco-axial connector and the terminal ends of said inner conductors forsaid outside co-axial connectors each tapering to a reduced diameter todefine a conical surface adapted to be engaged by the ends of saidfingers to bias said cup-shaped elements respectively in axialdirections against said contact surface on the end of said probe forsaid center switching means and said contact surfaces on the ends ofsaid probes for said outside switching means.

5. A unit according to claim 3, in which said transfer means comprise: acentral conducting disc mounted to said center switching means forrotation therewith; and two conducting sector plates respectivelymounted to said outside switching means for rotation therewith, theperipheries of said sector plates overlapping the periphery of saidcentral disc, said sector plates having sector portions adapted to makealternate electrical contact with said central disc upon rotation ofsaid switching means.

6. A unit according to claim 5, in which said central conducting disc issubstantially co-planar with said sector plates and includa a peripheralslot of thickness sufficient to receive the thickness of said sectorplates whereby the overlapping portions of the peripheries of saidsector plates are alternately sandwiched in said slot upon rotation ofsaid switching means.

7. A unit according to claim 3, in which said gear means include acenter spur gear secured to said center switching means for rotationtherewith, and two outside spur gears co-planar with said center spurgear, secured respectively to said two outside switching means andintermeshing `at diametrically opposite points with said center spurgear; said motor means being coupled to drive said center spur gearwhereby rotation thereof rotates said outside spur gears and associatedoutside switching means at the same speed and in the same direction.

8. A unit according to claim 3, in which said probe for said centerswitching means and said probes for said outside switching means includeelectrical conductors of given diameter gradually tapering to a reduceddiameter in a direction respectively towards the inner conductor of saidcenter co-axial connector and the inner conductors of said outsideco-axial connectors, said side walls in said first compartment includingtapered portions partially surrounding the respective tapering portionsof the probes whereby a relatively constant impedance is maintainedbetween the co-axial connectors and switching means.

9. A unit according to claim 8, in which said outside switching meanseach respectively include co-axial stubs extending from` said probesinto and terminating in said second compartment whereby the portions ofsaid switching means mounted in said bearing plate in combination withsaid stubs provide with said bearing plate a substantially uniform R-Fcavity end wall whereby losses of said electrical energy passing fromsaid center switching means to said outside switching means areminimized.

10. Agunit according to claim 5, in which each of said sector platesincludes at least one sector of given circumferential arcuate extent andrelative position such that one of said sector plates will make contactwith said central disc before the other of said sector plates breakscontact with said central disc.

11. A unit according to claim 10, in which one of said sector platesincludes a sector dimensioned differently from a sector on the other ofSaid sector plates whereby the electrical energy transferred to said oneof said sector plates is distinguished from the electrical energytransferred to the other of said sector plates.

12. A unit according to claim 3, in which said hollow casing ishermetically sealed and is filled with oil having a given dielectricconstant.

13. A transfer means for alternately passing electrical energy from aninput conductor to two output conductors, comprising, in combination: acentral disc connected to said input conductor; two outside platesconnected respectively to said two output conductors; means rotatablymounting said central disc and plates in co-planar relationship suchthat the peripheries of said plates respectively contact and overlapopposite peripheral portions of said central disc; means for rotatingsaid disc and each of said plates in synchronism to produce synchronousrotation of said disc and said plates; and conducting portions in eachof said plates positioned to make alternate contact with said centraldisc upon'rotation of said plates.

14. Thek subject matter of claim 13, in which said central disc includesa pair of co-axial conducting discs secured together at their hubportions and defining a peripheral slot therebetween, the thickness ofsaid slot being sufiicient to accommodate said conducting portions onsaid plates; said means for rotating said plates including means forrotating said plates including means for simultaneously rotating saidcentral disc at the same speed whereby the overlapping surfaces of saidslot and said conducting portions move at differential speeds to providea wiping contact.

15. A point contact means for passing electrical energy between twoelectrical conductors in co-axial alignment having their adjacent endsterminating in opposed relation to each other and in which one of saidconductors is rotated about its axis, comprising: a cup-shaped elementpositioned between said adjacent ends and having lateral slots defininga plurality of ngers, the end portion of the other of said conductorstapering to a reduced diameter to define a conical surface adapted t0 beengaged by the ends of said fingers, the base of said cup making pointcontact with the end of said one of said conductors, said fingers beingbiased radially inwardly to exert pressure on said conical surface ofsaid other of said conductors thereby urging said cup base axiallyagainst said end of` said one of said conductors.

References Cited in the file of this patent UNITED STATES PATENTS1,272,677 Krantz July 16, 1918 2,064,585 Atienza Dec. 15, 1936 2,449,138Phillips Sept. 14, 1948 2,695,385 Shunemann Nov. 23, 1954 2,757,341Lundstrom July 31, 1956

